Vehicle radios are becoming more and more sophisticated and as a result more expensive. The radio, being mounted with its control panel (i.e., bezel) located visibly on the vehicle instrument panel, is an easy target for thieves. This has led to an increase in theft of car radios. Consequently, some vehicle radios are now designed to be rendered inoperative if stolen from a vehicle.
Typical measures taken to discourage thieves include rendering the radio inoperable in a visible manner. This can be done by providing a radio alarm or by allowing for removal of the entire radio when the vehicle operator leaves the vehicle. This can also be done by requiring the entry of a security code to get the unit to play. Additionally, thieves can be discouraged by allowing an occupant to remove the entire radio bezel when the operator leaves the vehicle so the car radio loses its appearance as a car radio. Further, some are designed such that an operator may remove only an essential portion of a bezel to render the radio inoperable. Removing only the bezel is easier than requiring the removal of the entire radio since the overall radio tends to be heavy and bulky; also, this does not require occupants to remember a security code.
More often, a removable radio bezel is preferred because it is small and light weight, which makes it easy to carry around. The removable portion of the bezel has contacts exposed on its back side that are electrically connected to the radio buttons on the front of the bezel. When referring to front and back herein, front refers to the side of the radio facing the occupant on the instrument panel of the vehicle, while back refers to the side of the radio that extends into the instrument panel of the vehicle. The electrical contacts on the bezel can be fabricated as a separate part affixed to the removable bezel circuit board or they can be integral with the removable bezel circuit board. The contacts maintain surface contact with connector pins, mounted within a recess to the fixed portion of the radio, when the removable portion of the bezel is installed into the radio. The buttons and knobs on the removable bezel will then be electrically connected to the connector pins. The connector pins, in turn, are electrically connected to the main circuit board of the radio.
In general, the pins are directly connected to the main radio circuit board, and, thus, cannot be easily replaced. One drawback with this arrangement is that if the pins are bent or broken, during the assembly or operation of the vehicle, and therefore need to be replaced, the entire radio must be replaced since it is not economical to replace just the main circuit board in the radio.
Another particular drawback with radios which have removable bezels is that the connectors present a difficulty with electrostatic discharge (i.e., static electricity). This arises because the pins are exposed when the bezel is removed and, thus, if an occupant of the vehicle contacts the pins while having a build up of static electricity, this static electricity will discharge to the connector pins. This surge of electricity from the discharge can permanently damage integrated circuits in the radio.
As a result, three techniques in particular have been developed to protect the radio from this problem. First, the pins can be electrically isolated from the components on the main circuit board using additional electrical components mounted to the main circuit board, to safeguard the components on the circuit board from the surge of static electricity. However, the additional electrical components on the main circuit board will increase the cost of parts and assembly for each radio.
A second technique uses a shield, made of a non-conductive material, such as plastic, that will completely cover the pins while the bezel is removed, and move out of the way when the bezel is installed. Nevertheless, this still does not eliminate the chance that the occupant will accidentally move the cover out of the way and contact the pins, especially since the shield is non-conductive plastic and will not ground the electrostatic discharge.
In a third technique, a grounded conductive shield is placed around the pins to absorb the static electricity and transmit it to ground rather than the circuit board. But, if the shield does not sufficiently cover the pins, the static electricity may still discharge to the pins. The shield must also be located such that it is not too close to the pins, so the electric discharge will not arc between the grounded shield and the pins. The difficulty arises because the shield must both cover the pins sufficiently to prevent the discharge or absorb it when the bezel is removed and also easily move out of the way when the bezel is inserted to allow the pins to come into and maintain surface contact with the contacts on the bezel.
A further drawback with the pins on some existing connectors concerns pin bending because the pins are thin, flexible strands of bent wire shaped to protrude from the connector in a triangular shape. These wires can be easily bent should they be mishandled either during assembly of the radio or by a user of the radio. Additionally, since the shields do not closely conform to the cross-sectional area of the bent wires, there is insufficient support to prevent the bending even though the shields may generally provide a guide for the wires.
The thin flexible wires also create an additional potential problem with static discharge if a person needs to straighten out the pins, once bent, and uses an electrically conductive instrument such as a screw driver. The person has to move the protective shield out of the way to straighten the pins and thus risks exposing the pins to static discharge.